Browser tests for starting a drag-and-drop out of an OOPIF.

chrome/browser/drag_and_drop_browsertest.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.

[sky, 2016/11/15 00:37:55]

This test is ui specific, and it looks like it's also aura specific. Can you
move to c/b/ui/views and add _aura to the name?

[Łukasz Anforowicz, 2016/11/15 18:28:21]

Thanks for the suggestion.  I agree that it makes sense to move the new tests to
c/b/ui/views (given that the new test being added in this CL needs to simulate
the start of the drag and drop by going through ui-level simulation of the
mouse).

OTOH, the fact that the test today is implemented on top of aura is rather
accidental.  The test here mainly tests handling of drag-and-drop in //content
and Blink layers (to make sure drag-and-drop works across OOPIFs) - this
functionality needs to be hooked into aura, but routing mouse events across
multiple widgets should in general work across various UI platforms.  Ideally,
in the future the test would be amended to also work on Mac and/or Android.  I
think an Aura-only test is still a step in the right direction (and is
definitely needed to help prevent regressions in the drag-and-drop OOPIF support
that paulmeyer@ is working on and hopes to finish landing in the next week or
two).

So:

- I think I'd prefer to keep the test named in an aura-agnostic way

- I am open to suggestions for how to structure things, so that the
aura-specific things aren't mixed with ui-platform-agnostic stuff.  Maybe I
should move implementation of DragAndDropSimulator and DragStartWaiter classes
to an c/b/ui/views/drag_and_drop_test_utils_*aura*.cc while keeping non-virtual
(?) declarations of these classes in c/b/ui/views/drag_and_drop_test_utils.h.  I
haven't done that yet, because it seemed like an overkill given that 1)
currently there is *only* an aura implementation and 2) these classes are only
used from the 2 tests in drag_and_drop_browsertest.cc.

 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <memory>
 #include <string>
 
+#include "base/callback.h"
 #include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/sequenced_task_runner.h"
 #include "base/strings/pattern.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
-#include "content/browser/frame_host/frame_tree.h"
-#include "content/browser/frame_host/frame_tree_node.h"
-#include "content/browser/frame_host/render_frame_host_impl.h"
-#include "content/browser/web_contents/web_contents_impl.h"
+#include "base/threading/sequenced_task_runner_handle.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/tabs/tab_strip_model.h"
+#include "chrome/test/base/in_process_browser_test.h"
+#include "chrome/test/base/interactive_test_utils.h"
+#include "chrome/test/base/ui_test_utils.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/test/browser_test_utils.h"
 #include "content/public/test/content_browser_test.h"
 #include "content/public/test/content_browser_test_utils.h"
+#include "content/public/test/test_frame_navigation_observer.h"
 #include "content/public/test/test_utils.h"
-#include "content/shell/browser/shell.h"
 #include "net/base/escape.h"
 #include "net/dns/mock_host_resolver.h"
 #include "net/test/embedded_test_server/embedded_test_server.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "ui/aura/client/drag_drop_client.h"
 #include "ui/aura/client/drag_drop_delegate.h"
 #include "ui/aura/client/screen_position_client.h"
 #include "ui/aura/window.h"
 #include "ui/base/dragdrop/drag_drop_types.h"
 #include "ui/base/dragdrop/drop_target_event.h"
 #include "ui/base/dragdrop/os_exchange_data.h"
 #include "ui/gfx/geometry/point.h"
 #include "ui/gfx/geometry/rect.h"
 #include "url/gurl.h"
 
-namespace content {
+namespace chrome {
 
 namespace {
 
 // TODO(lukasza): Support testing on non-Aura platforms (i.e. Android + Mac?).
 //
 // Notes for the TODO above:
 //
 // - Why inject/simulate drag-and-drop events at the aura::Window* level.
 //
 //   - It seems better to inject into UI libraries to cover code *inside* these
 //     libraries.  This might complicate simulation a little bit (i.e. picking
 //     the right aura::Window and/or aura::client::DragDropDelegate to target),
 //     but otherwise important bits of code wouldn't get test coverage (i.e.
 //     directly injecting into RenderViewHost->DragTargetDragEnter seems wrong).
 //
 //   - In theory, we could introduce WebContentsImpl::DragTargetDragEnter (to be
 //     used by all UI platforms - so reused by web_contents_view_android.cc,
 //     web_contents_view_aura.cc, web_drag_dest_mac.mm), but it feels wrong - UI
 //     libraries should already know which widget is the target of the event and
 //     so should be able to talk directly to the right widget (i.e. WebContents
 //     should not be responsible for mapping coordinates to a widget - this is
 //     the job of the UI library).
 //
 // - Unknowns:
 //
 //   - Will this work for WebView and Plugin testing.
-//
-//   - Will this work for simulating dragging from WebContents into outside of
-//     the browser (without leaving OS drag&drop machinery in a weird state).
 
 // Test helper for simulating drag and drop happening in WebContents.
 class DragAndDropSimulator {
  public:
-  explicit DragAndDropSimulator(WebContents* web_contents)
+  explicit DragAndDropSimulator(content::WebContents* web_contents)
       : web_contents_(web_contents) {}
 
   // Simulates notification that |text| was dragged from outside of the browser,
   // into the specified |location| inside |web_contents|.
   // |location| is relative to |web_contents|.
   // Returns true upon success.
   bool SimulateDragEnter(gfx::Point location, const std::string& text) {
     ui::OSExchangeData data;
     data.SetString(base::UTF8ToUTF16(text));
     return SimulateDragEnter(location, data);
@@ skipping 66 matching lines @@
     *out_event_location = root_location;
   }
 
   // These are ui::DropTargetEvent::source_operations_ being sent when manually
   // trying out drag&drop of an image file from Nemo (Ubuntu's file explorer)
   // into a content_shell.
   static constexpr int kDefaultSourceOperations = ui::DragDropTypes::DRAG_MOVE |
                                                   ui::DragDropTypes::DRAG_COPY |
                                                   ui::DragDropTypes::DRAG_LINK;
 
-  WebContents* web_contents_;
+  content::WebContents* web_contents_;
   std::unique_ptr<ui::DropTargetEvent> active_drag_event_;
 
   DISALLOW_COPY_AND_ASSIGN(DragAndDropSimulator);
 };
 
+// Helper for waiting until a drag-and-drop starts (e.g. in response to a
+// mouse-down + mouse-move simulated by the test).
+class DragStartWaiter : public aura::client::DragDropClient {
+ public:
+  // Starts monitoring |web_contents| for a start of a drag-and-drop.
+  // While alive, prevents a real, OS-level drag-and-drop from starting
+  // for this particular |web_contents|.
+  explicit DragStartWaiter(content::WebContents* web_contents)
+      : web_contents_(web_contents),
+        message_loop_runner_(new content::MessageLoopRunner),
+        drag_started_(false) {
+    DCHECK(web_contents_);
+
+    // Intercept calls to the old DragDropClient.
+    gfx::NativeWindow root_window =
+        web_contents_->GetContentNativeView()->GetRootWindow();
+    old_client_ = aura::client::GetDragDropClient(root_window);
+    aura::client::SetDragDropClient(root_window, this);
+  }
+
+  ~DragStartWaiter() override {
+    // Restore the original DragDropClient.
+    gfx::NativeWindow root_window =
+        web_contents_->GetContentNativeView()->GetRootWindow();
+    aura::client::SetDragDropClient(root_window, old_client_);
+  }
+
+  // Waits until we almost report a drag-and-drop start to the OS
+  // (notifying the OS will be prevented to help the test continue
+  // without entering a nested message loop).
+  //
+  // Returns true if drag and drop has indeed started (and in this
+  // case populates |text|, |html| and other parameters with data
+  // that would have been passed to the OS).
+  bool WaitUntilDragStartIsIntercepted(
+      std::string* text,
+      std::string* html,
+      int* operation,
+      gfx::Point* location_inside_web_contents) {
+    message_loop_runner_->Run();

[sky, 2016/11/15 00:37:55]

Might StartDragAndDrop already have been called?

[Łukasz Anforowicz, 2016/11/15 18:28:21]

Yes and this is okay - in this case Run will immediately exit because our
implementation of StartDragAndDrop calls message_loop_runner_->Quit().  This
pattern is used in multiple places in content/public/test/browser_test_utils.cc
so I assume it is okay to also use this pattern here (examples from
browser_test_utils.cc - TitleWatcher calls Quit from TitleWatcher::TestTitle and
calls Run from TitleWatcher::WaitAndGetTitle.

+
+    if (!drag_started_)

[sky, 2016/11/15 00:37:55]

DCHECK?

[Łukasz Anforowicz, 2016/11/15 18:28:21]

Done.

+      return false;
+
+    *text = text_;

[sky, 2016/11/15 00:37:55]

Why not copy the pointers and set the values directly there? By that I mean make
the text_ member a std::string* ?

[Łukasz Anforowicz, 2016/11/15 18:28:21]

I think I'd prefer to leave this as-is:

1. This allows std::string text variable (and other related variables) to be
declared closer to the point of usage (i.e. right before
WaitUntilDragStartIsIntercepted, instead of before declaration of
DragStartWaiter).

2. This matches the pattern of other waiters from
//content/public/test/browser_test_utils.cc (i.e. TitleWatcher::observed_title_,
InputMsgWatcher::ack_result_ and ack_source_).

+    *html = html_;
+    *operation = operation_;
+    *location_inside_web_contents = location_inside_web_contents_;
+    return true;
+  }
+
+  // aura::client::DragDropClient overrides:
+

[sky, 2016/11/15 00:37:55]

no newline.

[Łukasz Anforowicz, 2016/11/15 18:28:21]

Done.

+  int StartDragAndDrop(const ui::OSExchangeData& data,
+                       aura::Window* root_window,
+                       aura::Window* source_window,
+                       const gfx::Point& screen_location,
+                       int operation,
+                       ui::DragDropTypes::DragEventSource source) override {
+    if (!drag_started_) {

[sky, 2016/11/15 00:37:55]

DCHECK(!drag_started_)?

[Łukasz Anforowicz, 2016/11/15 18:28:21]

Hmmm... okay.  I thought that this class should be a generic util that doesn't
fail a test if 2 drag-and-drops start and end, one after the other (although the
only test that uses DragStartWaiter today is indeed expecting only a single
drag-start).

+      drag_started_ = true;
+      message_loop_runner_->Quit();
+
+      base::string16 text;
+      if (data.GetString(&text))
+        text_ = base::UTF16ToUTF8(text);
+      else
+        text_ = "<no text>";
+
+      GURL base_url;
+      base::string16 html;
+      if (data.GetHtml(&html, &base_url))
+        html_ = base::UTF16ToUTF8(html);
+      else
+        html_ = "<no html>";
+
+      gfx::Rect bounds =
+          web_contents_->GetContentNativeView()->GetBoundsInScreen();
+      location_inside_web_contents_ =
+          screen_location - gfx::Vector2d(bounds.x(), bounds.y());
+
+      operation_ = operation;
+    }
+
+    // Forwarding to |old_client_| is undesirable, because test cannot control
+    // next steps after a nested drag-and-drop loop is entered at the OS level
+    // (as is the case in Windows, via DoDragDrop).  Instead, in the test we
+    // kind of ignore renderer's request to start drag and drop and never
+    // forward this request to the OS-specific layers.
+    return 0;
+  }
+
+  void DragCancel() override {
+    ADD_FAILURE() << "Unexpected call to DragCancel";
+  }
+
+  bool IsDragDropInProgress() override { return drag_started_; }
+
+ private:
+  content::WebContents* web_contents_;
+  scoped_refptr<content::MessageLoopRunner> message_loop_runner_;
+  aura::client::DragDropClient* old_client_;
+
+  // Data captured during the first intercepted StartDragAndDrop call.
+  bool drag_started_;
+  std::string text_;
+  std::string html_;
+  int operation_;
+  gfx::Point location_inside_web_contents_;
+};

[sky, 2016/11/15 00:37:55]

DISALLOW...

[Łukasz Anforowicz, 2016/11/15 18:28:21]

Ooops.  Done.

+
 // Helper for waiting for notifications from
 // content/test/data/drag_and_drop/event_monitoring.js
 class DOMDragEventWaiter {
  public:
   explicit DOMDragEventWaiter(const std::string& event_type_to_wait_for,
-                              const ToRenderFrameHost& target)
+                              const content::ToRenderFrameHost& target)
       : target_frame_name_(target.render_frame_host()->GetFrameName()),
         event_type_to_wait_for_(event_type_to_wait_for),
-        dom_message_queue_(
-            WebContents::FromRenderFrameHost(target.render_frame_host())) {}
+        dom_message_queue_(content::WebContents::FromRenderFrameHost(
+            target.render_frame_host())) {}
 
   // Waits until |target| calls reportDragEvent in
-  // content/test/data/drag_and_drop/event_monitoring.js with event_type
+  // chrome/test/data/drag_and_drop/event_monitoring.js with event_type
   // property set to |event_type_to_wait_for|.  (|target| and
   // |event_type_to_wait_for| are passed to the constructor).
   //
   // Returns the event details via |found_event| (in form of a JSON-encoded
-  // object).  See content/test/data/drag_and_drop/event_monitoring.js for keys
+  // object).  See chrome/test/data/drag_and_drop/event_monitoring.js for keys
   // and properties that |found_event| is expected to have.
   //
   // Returns true upon success.  It is okay if |response| is null.
   bool WaitForNextMatchingEvent(std::string* found_event) WARN_UNUSED_RESULT {
     std::string candidate_event;
     bool got_right_event_type = false;
     bool got_right_window_name = false;
     do {
       if (!dom_message_queue_.WaitForMessage(&candidate_event))
         return false;
 
       got_right_event_type = base::MatchPattern(
           candidate_event, base::StringPrintf("*\"event_type\":\"%s\"*",
                                               event_type_to_wait_for_.c_str()));
 
       got_right_window_name = base::MatchPattern(
           candidate_event, base::StringPrintf("*\"window_name\":\"%s\"*",
                                               target_frame_name_.c_str()));
     } while (!got_right_event_type || !got_right_window_name);
 
     if (found_event)
       *found_event = candidate_event;
 
     return true;
   }
 
  private:
   std::string target_frame_name_;
   std::string event_type_to_wait_for_;
-  DOMMessageQueue dom_message_queue_;
+  content::DOMMessageQueue dom_message_queue_;
+};

[sky, 2016/11/15 00:37:55]

DISALLOW...

[Łukasz Anforowicz, 2016/11/15 18:28:21]

Done.

+
+// Helper for verifying contents of DOM events associated with drag-and-drop.
+class DOMDragEventVerifier {
+ public:
+  DOMDragEventVerifier(){};

[sky, 2016/11/15 00:37:55]

no ';' and space between '()' and '{}'.

[Łukasz Anforowicz, 2016/11/15 18:28:21]

Done.

+
+  void set_expected_drop_effect(const std::string& value) {
+    expected_drop_effect_ = value;
+  }
+
+  void set_expected_effect_allowed(const std::string& value) {
+    expected_effect_allowed_ = value;
+  }
+
+  void set_expected_mime_types(const std::string& value) {
+    expected_mime_types_ = value;
+  }
+
+  // Returns a matcher that will match a std::string (drag event data - e.g.
+  // one returned by DOMDragEventWaiter::WaitForNextMatchingEvent) if it matches
+  // the expectations of this DOMDragEventVerifier.
+  testing::Matcher<std::string> Matches() const {
+    return testing::AllOf(
+        FieldMatches("drop_effect", expected_drop_effect_),
+        FieldMatches("effect_allowed", expected_effect_allowed_),
+        FieldMatches("mime_types", expected_mime_types_));
+  }
+
+ private:
+  static testing::Matcher<std::string> FieldMatches(
+      const std::string& field_name,
+      const std::string& expected_value) {
+    if (expected_value == "<no expectation>")
+      return testing::A<std::string>();
+
+    return testing::HasSubstr(base::StringPrintf(
+        "\"%s\":\"%s\"", field_name.c_str(), expected_value.c_str()));
+  }
+
+  std::string expected_drop_effect_ = "<no expectation>";
+  std::string expected_effect_allowed_ = "<no expectation>";
+  std::string expected_mime_types_ = "<no expectation>";
 };
 
 const char kTestPagePath[] = "/drag_and_drop/page.html";
 
 }  // namespace
 
-class DragAndDropBrowserTest : public ContentBrowserTest {
+class DragAndDropBrowserTest : public InProcessBrowserTest {
  public:
   DragAndDropBrowserTest(){};
 
  protected:
   void SetUpOnMainThread() override {
     host_resolver()->AddRule("*", "127.0.0.1");
     ASSERT_TRUE(embedded_test_server()->Start());
     content::SetupCrossSiteRedirector(embedded_test_server());
-    drag_simulator_.reset(new DragAndDropSimulator(shell()->web_contents()));
+    drag_simulator_.reset(new DragAndDropSimulator(web_contents()));
   }
 
-  // Navigates to content/test/data/drag_and_drop/page.html, with page origin
-  // and frame contents being controlled by the parameters.
-  bool NavigateToTestPage(const std::string& main_origin,
-                          const std::string& left_frame,
-                          const std::string& right_frame) {
-    GURL base_url = embedded_test_server()->GetURL(main_origin, kTestPagePath);
+  content::RenderFrameHost* left_frame() {
+    AssertTestPageIsLoaded();
+    return GetFrameByName("left");
+  }
 
-    std::string left_arg;
-    if (!left_frame.empty()) {
-      left_arg = net::EscapeQueryParamValue(
-          std::string("/cross-site/") + left_frame, true);
-    }
-    std::string right_arg;
-    if (!right_frame.empty()) {
-      right_arg = net::EscapeQueryParamValue(
-          std::string("/cross-site/") + right_frame, true);
-    }
-    std::string query = base::StringPrintf("left=%s&right=%s", left_arg.c_str(),
-                                           right_arg.c_str());
-    GURL::Replacements query_replacement;
-    query_replacement.SetQueryStr(query);
-    GURL target_url = base_url.ReplaceComponents(query_replacement);
+  content::RenderFrameHost* right_frame() {
+    AssertTestPageIsLoaded();
+    return GetFrameByName("right");
+  }
 
-    return NavigateToURL(shell(), target_url);
+  content::WebContents* web_contents() {
+    return browser()->tab_strip_model()->GetActiveWebContents();
   }
 
+  //////////////////////
+  // Navigation helpers.
+
+  bool NavigateToTestPage(const std::string& origin_of_main_frame) {
+    GURL url =
+        embedded_test_server()->GetURL(origin_of_main_frame, kTestPagePath);
+    ui_test_utils::NavigateToURL(browser(), url);
+    return web_contents()->GetLastCommittedURL() == url;
+  }
+
+  // Navigates the left frame to |filename| (found under
+  // chrome/test/data/drag_and_drop directory).
+  bool NavigateLeftFrame(const std::string& origin,
+                         const std::string& filename) {
+    AssertTestPageIsLoaded();
+    return NavigateNamedFrame("left", origin, filename);
+  }
+
+  // Navigates the right frame to |filename| (found under
+  // chrome/test/data/drag_and_drop directory).
+  bool NavigateRightFrame(const std::string& origin,
+                          const std::string& filename) {
+    AssertTestPageIsLoaded();
+    return NavigateNamedFrame("right", origin, filename);
+  }
+
+  ////////////////////////////////////////////////////////////
+  // Simulation of starting a drag-and-drop (using the mouse).
+
+  bool SimulateMouseDownAndDragStartInLeftFrame() {
+    AssertTestPageIsLoaded();
+    if (!SimulateMouseMove(kMiddleOfLeftFrame) || !SimulateMouseDown() ||
+        !SimulateMouseMove(expected_location_of_drag_start_in_left_frame()))
+      return false;
+
+    return true;
+  }
+
+  gfx::Point expected_location_of_drag_start_in_left_frame() {
+    // TODO(crbug.com/653490): The delta below should exceed kDragThresholdX and
+    // kDragThresholdY from MouseEventManager.cpp in blink.  Ideally, it would
+    // come from the OS instead.
+    return kMiddleOfLeftFrame + gfx::Vector2d(10, 10);
+  }
+
+  bool SimulateMouseUp() {
+    return ui_test_utils::SendMouseEventsSync(ui_controls::LEFT,
+                                              ui_controls::UP);
+  }
+
+  ////////////////////////////////////////////////////////////////////
+  // Simulation of dragging from outside the browser into web contents
+  // (using DragAndDropSimulator, not simulating mouse events).
+
   bool SimulateDragEnterToRightFrame(const std::string& text) {
     AssertTestPageIsLoaded();
     return drag_simulator_->SimulateDragEnter(kMiddleOfRightFrame, text);
   }
 
   bool SimulateDropInRightFrame() {
     AssertTestPageIsLoaded();
     return drag_simulator_->SimulateDrop(kMiddleOfRightFrame);
   }
 
-  RenderFrameHost* right_frame() {
-    AssertTestPageIsLoaded();
-    return GetFrameByName("right");
+ private:
+  bool SimulateMouseDown() {
+    return ui_test_utils::SendMouseEventsSync(ui_controls::LEFT,
+                                              ui_controls::DOWN);
   }
 
- private:
-  RenderFrameHost* GetFrameByName(const std::string& name_to_find) {
-    WebContentsImpl* web_contents =
-            static_cast<WebContentsImpl*>(shell()->web_contents());
-    FrameTree* frame_tree = web_contents->GetFrameTree();
-    return frame_tree->FindByName(name_to_find)->current_frame_host();
+  bool SimulateMouseMove(const gfx::Point& location_inside_web_contents) {
+    gfx::Rect bounds = web_contents()->GetContainerBounds();
+    return ui_test_utils::SendMouseMoveSync(
+        gfx::Point(bounds.x() + location_inside_web_contents.x(),
+                   bounds.y() + location_inside_web_contents.y()));
+  }
+
+  bool NavigateNamedFrame(const std::string& frame_name,
+                          const std::string& origin,
+                          const std::string& filename) {
+    content::RenderFrameHost* frame = GetFrameByName(frame_name);
+    if (!frame)
+      return false;
+
+    std::string script;
+    int response = 0;
+
+    // Navigate the frame and wait for the load event.
+    script = base::StringPrintf(
+        "location.href = '/cross-site/%s/drag_and_drop/%s';\n"
+        "setTimeout(function() { domAutomationController.send(42); }, 0);",
+        origin.c_str(), filename.c_str());
+    content::TestFrameNavigationObserver observer(frame);
+    if (!content::ExecuteScriptAndExtractInt(frame, script, &response))
+      return false;
+    if (response != 42)
+      return false;
+    observer.Wait();
+
+    // Wait until frame contents (e.g. images) have painted (which should happen
+    // in the animation frame that *starts* after the onload event - therefore
+    // we need to wait for 2 animation frames).
+    script = std::string(
+        "requestAnimationFrame(function() {\n"
+        "  requestAnimationFrame(function() {\n"
+        "    domAutomationController.send(43);\n"
+        "  });\n"
+        "});\n");
+    if (!content::ExecuteScriptAndExtractInt(frame, script, &response))
+      return false;
+    if (response != 43)
+      return false;
+
+    return true;
+  }
+
+  content::RenderFrameHost* GetFrameByName(const std::string& name_to_find) {
+    content::RenderFrameHost* result = nullptr;
+    for (content::RenderFrameHost* rfh : web_contents()->GetAllFrames()) {
+      if (rfh->GetFrameName() == name_to_find) {
+        if (result) {
+          ADD_FAILURE() << "More than one frame named "
+                        << "'" << name_to_find << "'";
+          return nullptr;
+        }
+        result = rfh;
+      }
+    }
+
+    EXPECT_TRUE(result) << "Couldn't find a frame named "
+                        << "'" << name_to_find << "'";
+    return result;
   }
 
   void AssertTestPageIsLoaded() {
-    ASSERT_EQ(kTestPagePath,
-              shell()->web_contents()->GetLastCommittedURL().path());
+    ASSERT_EQ(kTestPagePath, web_contents()->GetLastCommittedURL().path());
   }
 
   std::unique_ptr<DragAndDropSimulator> drag_simulator_;
 
   // Constants with coordinates within content/test/data/drag_and_drop/page.html
   const gfx::Point kMiddleOfLeftFrame = gfx::Point(200, 200);
   const gfx::Point kMiddleOfRightFrame = gfx::Point(400, 200);
 
   DISALLOW_COPY_AND_ASSIGN(DragAndDropBrowserTest);
 };
 
 IN_PROC_BROWSER_TEST_F(DragAndDropBrowserTest, DropTextFromOutside) {
-  ASSERT_TRUE(NavigateToTestPage("a.com",
-                                 "",  // Left frame is unused by this test.
-                                 "c.com/drag_and_drop/drop_target.html"));
+  ASSERT_TRUE(NavigateToTestPage("a.com"));
+  ASSERT_TRUE(NavigateRightFrame("b.com", "drop_target.html"));
 
+  // Setup test expectations.
+  DOMDragEventVerifier expected_dom_event_data;
+  expected_dom_event_data.set_expected_drop_effect("none");
+  expected_dom_event_data.set_expected_effect_allowed("all");
+  expected_dom_event_data.set_expected_mime_types("text/plain");
+
+  // Drag text from outside the browser into/over the right frame.
   {
-    std::string dragover_event;
     DOMDragEventWaiter dragover_waiter("dragover", right_frame());
     ASSERT_TRUE(SimulateDragEnterToRightFrame("Dragged test text"));
+
+    std::string dragover_event;
     ASSERT_TRUE(dragover_waiter.WaitForNextMatchingEvent(&dragover_event));
-    EXPECT_THAT(dragover_event, testing::HasSubstr("\"drop_effect\":\"none\""));
-    EXPECT_THAT(dragover_event,
-                testing::HasSubstr("\"effect_allowed\":\"all\""));
-    EXPECT_THAT(dragover_event,
-                testing::HasSubstr("\"mime_types\":\"text/plain\""));
+    EXPECT_THAT(dragover_event, expected_dom_event_data.Matches());
   }
 
+  // Drop into the right frame.
   {
-    std::string drop_event;
     DOMDragEventWaiter drop_waiter("drop", right_frame());
     ASSERT_TRUE(SimulateDropInRightFrame());
+
+    std::string drop_event;
     ASSERT_TRUE(drop_waiter.WaitForNextMatchingEvent(&drop_event));
-    EXPECT_THAT(drop_event, testing::HasSubstr("\"drop_effect\":\"none\""));
-    EXPECT_THAT(drop_event, testing::HasSubstr("\"effect_allowed\":\"all\""));
-    EXPECT_THAT(drop_event,
-                testing::HasSubstr("\"mime_types\":\"text/plain\""));
+    EXPECT_THAT(drop_event, expected_dom_event_data.Matches());
   }
 }
 
+// The test is disabled on Ozone because of trouble with mouse simulation
+// during the test - see https://crbug.com/665042.
+#if defined(USE_OZONE)
+#define MAYBE_DragStartInFrame DISABLED_DragStartInFrame
+#else
+#define MAYBE_DragStartInFrame DragStartInFrame
+#endif
+IN_PROC_BROWSER_TEST_F(DragAndDropBrowserTest, MAYBE_DragStartInFrame) {
+  std::string frame_site = "b.com";
+  ASSERT_TRUE(NavigateToTestPage("a.com"));
+  ASSERT_TRUE(NavigateLeftFrame(frame_site, "image_source.html"));
+
+  // Setup test expectations.
+  // (dragstart event handler in image_source.html is asking for "copy" only).
+  DOMDragEventVerifier expected_dom_event_data;
+  expected_dom_event_data.set_expected_drop_effect("none");
+  expected_dom_event_data.set_expected_effect_allowed("copy");
+  expected_dom_event_data.set_expected_mime_types(
+      "Files,text/html,text/uri-list");
+
+  // Start the drag in the left frame.
+  DragStartWaiter drag_start_waiter(web_contents());
+  DOMDragEventWaiter dragstart_event_waiter("dragstart", left_frame());
+  EXPECT_TRUE(SimulateMouseDownAndDragStartInLeftFrame());
+
+  // Verify Javascript event data.
+  {
+    std::string dragstart_event;
+    EXPECT_TRUE(
+        dragstart_event_waiter.WaitForNextMatchingEvent(&dragstart_event));
+    EXPECT_THAT(dragstart_event, expected_dom_event_data.Matches());
+  }
+
+  // Verify data being passed to the OS.
+  {
+    std::string text;
+    std::string html;
+    int operation = 0;
+    gfx::Point location_inside_web_contents;
+    EXPECT_TRUE(drag_start_waiter.WaitUntilDragStartIsIntercepted(

[sky, 2016/11/15 00:37:55]

SHould this be an assert? If it fails is there really any point in continuing?

[Łukasz Anforowicz, 2016/11/15 18:28:21]

N/A - after addressing earlier comments WaitUntilDragStartIsIntercepted doesn't
return a boolean anymore (because it is not possible for it to return until
drag-start actually happened).

+        &text, &html, &operation, &location_inside_web_contents));
+    EXPECT_EQ(embedded_test_server()->GetURL(frame_site,
+                                             "/image_decoding/droids.jpg"),
+              text);
+    EXPECT_THAT(html,
+                testing::MatchesRegex("<img .*src=\""
+                                      "http://.*/image_decoding/droids.jpg"
+                                      "\">"));
+    EXPECT_EQ(expected_location_of_drag_start_in_left_frame(),
+              location_inside_web_contents);
+    EXPECT_EQ(ui::DragDropTypes::DRAG_COPY, operation);
+  }
+
+  // Try to leave everything in a clean state.
+  SimulateMouseUp();
+}
+
 }  // namespace chrome